/Engine/Plugins/FX/Niagara/Source/Niagara/Public/NiagaraRibbonRendererProperties.h
virtual void GetUsedMaterials ( const [FNiagaraEmitterInstance](API\Plugins\Niagara\FNiagaraEmitterInstance) * InEmitter, [TArray](API\Runtime\Core\Containers\TArray)< [UMaterialInterface](API\Runtime\Engine\Materials\UMaterialInterface) * > & OutMaterials ) const